A new species of Fannia (Diptera, Fanniidae) from Yunnan, China

Abstract A new species of the genus Fannia (Diptera, Fanniidae) is described from Yunnan, China, namely Fanniabaihualingensissp. nov. The male habitus as well as terminalia are documented with focus-stacked photographs. A detailed comparison of new species with related species is provided.


Introduction
The Fanniidae (Diptera, Muscoidea) are cosmopolitan flies with over 400 described species. Around 160 species have been found from China, including one species of Euryomma Stein, two species of Piezura Rondani, and 157 species of Fannia Robineu-Desvoidy. Of these species, 61.25% of them (i.e., 98 species) are endemic to China.
The Fannia posticata-group was established by Chillcott (1961), originally as the Fannia pretiosa-group. Wang et al. (2010) reviewed the F. posticata-group and expanded it to include 21 species.
Yunnan is the highest biodiversity hotspot in China. In this study, we describe a new species of the Fannia posticata-group from Yunnan, Fannia baihualingensis sp. nov., and provide an extensive documentation of the adult male of this species.

Materials and methods
Terminology follows McAlpine (1981) and Stuckenberg (1999). Methods for the preparation of terminalia and illustrations follow Zhang et al. (2013). All type specimens of the new species are deposited in the Museum of Beijing Forestry University, Beijing, China (MBFU).
Abbreviations used throughout the text are as follows: acr acrostichal seta, ad anterodorsal seta, av anteroventral seta, d dorsal seta, p posterior seta, pd posterodorsal seta, pv posteroventral seta. Paratypes 2 ♂, same data as holotype (MBFU). Diagnosis. Fannia baihualingensis can be readily identified by the following character states: distinctly projecting lower calypter; hind coxa bare on posterior surface; hind femur arcuate, with clump of long black setae on swollen part; hind tibia with two av, hook-like projection on lower margin of cercus curved outward; surstylus very long and slender; bacilliform process absent.
Description. Male. Body length 5.00-6.50 mm (2 specimens measured). Eye bare. Fronto-orbital plate and parafacial with grayish-silvery pollinosity. Frons slightly narrower than the distance between two posterior ocelli at narrowest point, frontal vitta black, frontal setae 7-9, stout. Postocular setae in 1 row, without occipital seta behind the postocular setae on vertex. Parafacial bare, at middle about 3/4 as wide as the width of postpedicel. Antenna grayish black, postpedicel 2 × longer than wide, arista black and short plumose, slightly swollen in basal part. Epistoma not projecting beyond vibrissal angle, vibrissal angle behind frontal angle in profile, subvibrissal setae in 1 row, lateral with one 1 of short setae. Proboscis stout. Palpus black, claviform, longer than the length of prementum.
Thorax ground color black, without distinct vitta. Postpronotal lobe gray. Presutural acr biserial, hair-like, only prescutellar pairs slightly stout, dorsocentrals 2+3, intra-alars 2, supra-alars 2, postpronotals 2, notopleurals 2. Katepisternal setae 1+1, katepisternum without ventral spine. Scutellum black, with 3 pairs of lateral, 2 pair of discal, and 2 pair of apical setae. Calypters white, the lower one slightly projecting beyond the upper one. Wing brownish; veins brown; tegula dark brown; basicosta brownish-yellow; costal spine inconspicuous; node of Rs bare on ventral and dorsal surfaces; vein R 4+5 straight; crossveins without obvious cloud; haltere yellow but brown in basal part. Legs entirely black. Fore femur with complete d, pd, and pv rows, fore tibia with 1 pd seta; mid coxa with spin-like setae, mid femur with complete ad row, becoming gradually shorter and denser towards apex, pv row complete, in 1 row, ad rows weak, 5 setae strong in distal part, mid tibia slightly swollen in distal 2/3, with 1 ad and 1 pd; hind coxa bare on posterior surface, hind femur curved and arcuate, swollen at apex below, the swollen part with a clump of long black setae on postero-ventral (Fig. 1E), antero-ventral surface with a complete series of setae, (the apical 4 longer and stronger), hind tibia with 2 av.
Compared with F. arcuata, F. curvipes, and F. fasciculata, only the hind tibia of F. arcuata has a complete ad row. Fannia curvipes, F. fasciculate, and Fannia baihualingensis sp. nov. are all only with one ad. The male terminalia of F. arcuata is also very different from those of the other three species (Fig. 3B). The male terminalia of F. curvipes, F. fasciculate, and Fannia baihualingensis sp. nov. are very similar, especially the shape of surstylus. However, the new species can be identified by the shape of the cercus. In F. curvipes the cercal plate is very slender in its apical half and prolonged into an upcurved process (Fig. 3A). The cercus of F. fasciculata is slender and bifurcate at the apex (Fig. 3C). The cercus of F. baihualingensis sp. nov. is slightly rounded, with the hook-like projection on its lower margin strongly curved outward (Fig. 3D).
Fannia baihualingensis sp. nov. can also be distinguished from F. fasciculata by some external characters, such as the number of av on hind tibia: the new species has only two av, while F. fasciculata has four or five.
Etymology. The new species is named after its type locality, Baihualing. Distribution. Known only from the type locality in Yunnan, China.